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Message-ID: <20121126203706.28840.78130.stgit@lambeau>
Date: Mon, 26 Nov 2012 14:37:06 -0600
From: Michael Wolf <mjw@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: riel@...hat.com, kvm@...r.kernel.org, peterz@...radead.org,
mtosatti@...hat.com, glommer@...allels.com, mingo@...hat.com
Subject: [PATCH 4/5] Add a timer to allow the separation of consigned from
steal time.
Add a timer to the host. This will define the period. During a period
the first n ticks will go into the consigned bucket. Any other ticks that
occur within the period will be placed in the stealtime bucket.
Signed-off-by: Michael Wolf <mjw@...ux.vnet.ibm.com>
---
arch/x86/include/asm/kvm_host.h | 10 +++++++++
arch/x86/include/asm/paravirt.h | 2 +-
arch/x86/kvm/x86.c | 42 ++++++++++++++++++++++++++++++++++++++-
3 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 434d378..4794c95 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -41,6 +41,8 @@
#define KVM_PIO_PAGE_OFFSET 1
#define KVM_COALESCED_MMIO_PAGE_OFFSET 2
+#define KVM_STEAL_TIMER_DELAY 100000000UL
+
#define CR0_RESERVED_BITS \
(~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
| X86_CR0_ET | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM \
@@ -353,6 +355,14 @@ struct kvm_vcpu_arch {
bool tpr_access_reporting;
/*
+ * timer used to determine if the time should be counted as
+ * steal time or consigned time.
+ */
+ struct hrtimer steal_timer;
+ u64 current_consigned;
+ u64 consigned_limit;
+
+ /*
* Paging state of the vcpu
*
* If the vcpu runs in guest mode with two level paging this still saves
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index d39e8d0..6db79f9 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -196,7 +196,7 @@ struct static_key;
extern struct static_key paravirt_steal_enabled;
extern struct static_key paravirt_steal_rq_enabled;
-static inline u64 paravirt_steal_clock(int cpu, u64 *steal, u64 *consigned)
+static inline void paravirt_steal_clock(int cpu, u64 *steal, u64 *consigned)
{
PVOP_VCALL3(pv_time_ops.steal_clock, cpu, steal, consigned);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 683b531..c91f4c9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1546,13 +1546,32 @@ static void kvmclock_reset(struct kvm_vcpu *vcpu)
static void accumulate_steal_time(struct kvm_vcpu *vcpu)
{
u64 delta;
+ u64 steal_delta;
+ u64 consigned_delta;
if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
return;
delta = current->sched_info.run_delay - vcpu->arch.st.last_steal;
vcpu->arch.st.last_steal = current->sched_info.run_delay;
- vcpu->arch.st.accum_steal = delta;
+
+ /* split the delta into steal and consigned */
+ if (vcpu->arch.current_consigned < vcpu->arch.consigned_limit) {
+ vcpu->arch.current_consigned += delta;
+ if (vcpu->arch.current_consigned > vcpu->arch.consigned_limit) {
+ steal_delta = vcpu->arch.current_consigned
+ - vcpu->arch.consigned_limit;
+ consigned_delta = delta - steal_delta;
+ } else {
+ consigned_delta = delta;
+ steal_delta = 0;
+ }
+ } else {
+ consigned_delta = 0;
+ steal_delta = delta;
+ }
+ vcpu->arch.st.accum_steal = steal_delta;
+ vcpu->arch.st.accum_consigned = consigned_delta;
}
static void record_steal_time(struct kvm_vcpu *vcpu)
@@ -6203,11 +6222,25 @@ bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu)
struct static_key kvm_no_apic_vcpu __read_mostly;
+enum hrtimer_restart steal_timer_fn(struct hrtimer *data)
+{
+ struct kvm_vcpu *vcpu;
+ ktime_t now;
+
+ vcpu = container_of(data, struct kvm_vcpu, arch.steal_timer);
+ vcpu->arch.current_consigned = 0;
+ now = ktime_get();
+ hrtimer_forward(&vcpu->arch.steal_timer, now,
+ ktime_set(0, KVM_STEAL_TIMER_DELAY));
+ return HRTIMER_RESTART;
+}
+
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
struct page *page;
struct kvm *kvm;
int r;
+ ktime_t ktime;
BUG_ON(vcpu->kvm == NULL);
kvm = vcpu->kvm;
@@ -6251,6 +6284,12 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
kvm_async_pf_hash_reset(vcpu);
kvm_pmu_init(vcpu);
+ /* Initialize and start a timer to capture steal and consigned time */
+ hrtimer_init(&vcpu->arch.steal_timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_REL);
+ vcpu->arch.steal_timer.function = &steal_timer_fn;
+ ktime = ktime_set(0, KVM_STEAL_TIMER_DELAY);
+ hrtimer_start(&vcpu->arch.steal_timer, ktime, HRTIMER_MODE_REL);
return 0;
fail_free_mce_banks:
@@ -6269,6 +6308,7 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
int idx;
+ hrtimer_cancel(&vcpu->arch.steal_timer);
kvm_pmu_destroy(vcpu);
kfree(vcpu->arch.mce_banks);
kvm_free_lapic(vcpu);
--
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